Proliferation Of Human Bone Cells Research Articles

Ethanol inhibits human bone cell proliferation and function in vitro

The direct effects of ethanol on human bone cell proliferation and function were studied in vitro. Normal human osteoblasts from trabecular bone chips were prepared by collagenase digestion. Exposure of these osteoblasts to ethanol in concentrations of 0.05% to 1% for 22 hours induced a dose-dependent reduction in bone cell DNA synthesis as assessed by incorporation of 3H-thymidine. After 72 hours of ethanol exposure in concentrations of 0.01% to 1%, protein synthesis as measured by 3H-proline incorporation into trichbroacetic acid (TCA)-precipitable material was reduced in a dose-dependent manner. Human bone cell protein concentrations and alkaline phosphatase total activity were significantly reduced after exposure to 1% ethanol for 72 hours, but not with lower concentrations of ethanol. This reduction in osteoblast proliferation and activity may partially explain the development of osteopenia in humans consuming excessive amounts of ethanol.

Sodium fluoride does not increase human bone cell proliferation or protein synthesisin vitro

The efficacy of sodium fluoride therapy for osteoporosis remains controversial. Evidence from clinical studies and from animals receiving fluoride has suggested that fluoride might act on bone to increase osteoblast numbers and matrix synthesis. In order to examine the hypothesis that fluoride has a direct mitogenic or anabolic action on the osteoblast, we tested the effect of fluoride on first passage human osteoblastic bone cells grown from collagenase-treated trabecular bone fragments. Under a variety of culture conditions, including both medium supplementation with serum and with a chemically defined medium, fluoride in doses ranging from 10(-6) to 10(-3) M did not alter cell proliferation as measured either by thymidine incorporation or by direct cell counting. Furthermore, exposure to fluoride under conditions of low serum supplementation did not alter either the total protein synthesis of the cells or their biosynthetic profile. These data suggest that fluoride does not act in vitro upon differentiated osteoblastic bone cells derived from adult human patients.

Stimulation of the proliferation of human bone cells in vitro by human monocyte products with interleukin-1 activity.

The process of induction of bone formation, which follows bone resorption during normal and pathological bone turnover, is well documented. However, the mechanisms responsible for this process are unclear. Mononuclear phagocytes present at the sites of bone remodeling could play a role in this "coupling" of bone formation to bone resorption. This study was designed to investigate such a possibility. By measuring both the increase in [3H]thymidine incorporation and in cell number, we found that human monocytes in culture released factors capable of stimulating the proliferation of osteoblast-like cells derived from human bone. Rapidly dividing cells exhibited a greater response to interleukin 1 (IL-1) than confluent cells. The factors are similar to IL-1 in that they exhibited the same molecular weight and isoelectric point, were present in fractions that contained IL-1 activity after gel filtration chromatography and isoelectric focusing, and showed similar dose-response characteristics. Proliferation was more marked when prostaglandin production by the cells, which was also stimulated by these factors, was inhibited by indomethacin. A factor produced by monocytes that affects osteoblast activity may be important in the coupling of osteoclast and osteoblast actions.